CINCPAC Fleet Headquarters, also known as Commander in Chief Pacific Fleet Headquarters or COMPACFLT Headquarters, is a historic military building on Makalapa Drive in Joint Base Pearl Harbor–Hickam, on the island of Oahu in the US state of Hawaii. Built during World War II in 1942, it served as the headquarters of Admiral Chester W. Nimitz from 1942 through 1945, while he was Commander-in-Chief, Pacific Fleet and Commander-in-Chief, Pacific Ocean Areas, during World War II. Commanding land, sea, and air forces, Admiral Nimitz had major responsibility for campaigns such as the Battle of Midway, the liberation of Guam, and the seizure of Saipan and Tinian in the Marianas. It was designated a National Historic Landmark for this role in 1987.